[web-devel] Automatically making every Cereal.Serialize instance of PersistField - bad idea?
mxcantor at gmail.com
Fri Jan 28 07:28:55 CET 2011
I should have added, as long as the type-checker terminates and doesn't go into an infinite loop, is there any danger in doing this?
On Jan 28, 2011, at 2:24 PM, Max Cantor wrote:
> With a bit of code, you can save a lot of effort if you add new types to Persistent:
> instance Cereal.Serialize a => PersistField a where
> toPersistValue a = PersistByteString $ Cereal.encode a
> fromPersistValue (PersistByteString b) = Cereal.decode b
> fromPersistValue _ = Left "bad type for cereal encoded data"
> sqlType _ = SqlBlob
> isNullable _ = False
> BUT, this requires UndecidableInstances. Is this a bad idea?
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